package com.rd.student.dashuju.wangbo.exercise0728;

import java.util.Scanner;

public class TestRecu {

    public static void main(String[] args) {
        System.out.println(fib(new Scanner(System.in).nextInt()));
    }

    public static int fib(int n) {
        if (n == 1) return 1;
        if (n == 2) return 1;
        int A = fib(n - 1);
        int B = fib(n - 2);
        return A + B;
    }
}
